Scope Mount Finder

Fit a 34 mm scope in 30 mm rings

Why a 34 mm tube does not fit 30 mm rings and what to buy instead.

Will not fitA 34 mm scope will not fit 30 mm rings. The tube is 4 mm larger than the ring bore, so the ring cannot close. Buy 34 mm rings.
Optic34 mm scope34 mm tube
interface
Mountthe 34 mm tube is larger than a 30 mm ring bore
seats on
Rail30 mm ringsbore too small for a 34 mm tube
Fit readoutBench figures
Fitment
Why it fails
34 mm tube exceeds the 30 mm ring bore
Inserts
reducer inserts only step a larger ring down, never up
What to fit it with

Rings must match the tube. A 34 mm tube is larger than a 30 mm ring bore, so a 30 mm ring physically cannot close around it. There is no adapter that enlarges a ring.

Reducer inserts exist but only work the other way, letting a larger ring hold a smaller tube, for example a 34 mm ring with inserts holding a 30 mm scope. For a 34 mm scope, buy 34 mm rings.

Related fitments

Sources: 1in, 30mm, 34mm scope tubes and rings, Weaver Mounts · Scope tube sizes explained, Victoptics · How to select rifle scope rings, Outdoorsmans